Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology | 2021
Maternal and fetal characteristics predicting Cesarean risk following induction of labor: pooled analysis of PROBAAT trials.
Abstract
OBJECTIVE\nInduction of labor (IOL) is one of the most widely used obstetric interventions. However, one-fifth of labor inductions end with cesarean section (CS). We aimed to assess maternal and fetal characteristics that influence the likelihood of CS following IOL by indications.\n\n\nMETHODS\nThis is a secondary analysis of pooled data from four randomized control trials on IOL. The main outcomes of this analysis were CS for failure to progress (FTP) and CS for suspected fetal compromise (SFC). Restricted cubic spline was used to explore non-linear relationships for continuous characteristics. Optimal cut-offs for non-linear patterns were determined with maximized Area Under the Curve. Adjusted odds ratios were computed with logistic regressions.\n\n\nRESULTS\nAmong a total of 2990 women, 313 women had CS for FTP and 227 for SFC. Regarding the risk of CS for FTP, women aged 30-35 were at elevated risk (aOR 1.51, 95% CI 1.15-1.99) compared with younger women. Nulliparous women had a higher risk than multiparous women (aOR 8.07, CI 5.34-12.18). Incremental BMI increased the risk (aOR 1.06, CI 1.04-1.08). Higher birthweight percentile, using 20-49.9% as a reference, also carried a higher risk for CS due to FTP (for 80-89.9%, aOR 2.66, CI 2.71-4.07; for ≥90% aOR 4.08, CI 2.75-6.05). For CS due to SFC, incremental maternal age (aOR 1.09, CI 1.05-1.12) and BMI (aOR 1.05, CI 1.03-1.08) were associated with increased risk. Compared with multiparous women, nulliparous women had increased risk (aOR 5.91, CI 3.76-9.28). Low birthweight percentile (<10%) carried a significantly higher risk for CS due to SFC (aOR 1.93, CI 1.22-3.05) compared to those in the 20-49.9% category. Bishop score did not demonstrate a significant relationship with predicting CS rate as compared to vaginal delivery.\n\n\nCONCLUSIONS\nMaternal age, BMI, parity, and birthweight percentile are predictors of CS following IOL both for FTP and SFC, but with different directions and magnitude. These characteristics should be considered in combination with the Bishop score to stratify the risk of CS for different indications. This article is protected by copyright. All rights reserved.